Dadaism refers to a direction in art critical of culture that began in 1916 with the Cabaret Voltaire in Zurich. The name dada comes from a children’s expression for "rocking horse" in French, which Hugo Hall apparently picked from a dictionary at random. These two elements of nonsense and chance incorporate the most important features of Dadaism. Dada artists agitated against what they viewed as outmoded social and cultural structures; above all they protested war, whose senselessness they sought to manifest. Dada art is the art of nonsense, without meaning; an anti-art, so to speak, whose content is set down in a manifesto by Tristan Tzara. Experimenting with the very notion of art, Dada declared everyday objects to be works of art, and blurred the boundaries between genres. Dada plays were bruitist concerts of noise accompanied by grotesque dances and poems of incoherent wordplay, all served up by people wearing absurd costumes. All of these events were intended to provoke the audience, holding up a mirror to it. The machine was a popular Dada theme, though it was not glorified as in Futurism, but used to symbolize the failure of society. From its Zurich headquarters the movement soon spread across Europe and even to the U.S., albeit with certain distinctions: while in New York, the condition of modern art was the focus, in Germany, Dadaists were more concerned about a national social crisis following the war. In France, Dada interest in the mechanization of subconscious processes easily accounts for Surrealism’s later affinity with Dadaism. Dada artists include Hans Arp, Johannes Baader, Hugo Ball, Marcel Duchamp, Max Ernst, Hans Höch, Francis Picabia, Kurt Schwitters, and Tristan Tzara.